#include <assert.h>
#include <stdlib.h>
#include <stdio.h>
#include <wlr/interfaces/wlr_output.h>
#include <wlr/util/log.h>
#include "backend/fbdev.h"
#include "util/signal.h"
#include "drm_fourcc.h"
#include <wlr/render/drm_format_set.h>
#include <sys/mman.h>

static struct wlr_drm_format_set output_fmt_set;

static const uint32_t SUPPORTED_OUTPUT_STATE =
	WLR_OUTPUT_STATE_BACKEND_OPTIONAL |
	WLR_OUTPUT_STATE_BUFFER |
	WLR_OUTPUT_STATE_MODE;

static struct wlr_fbdev_output *fbdev_output_from_output(
		struct wlr_output *wlr_output) {
	assert(wlr_output_is_fbdev(wlr_output));
	return (struct wlr_fbdev_output *)wlr_output;
}

static bool output_set_custom_mode(struct wlr_fbdev_output *output,
		int32_t width, int32_t height, int32_t refresh) {
	if (refresh <= 0) {
		refresh = FBDEV_DEFAULT_REFRESH;
	}

	output->frame_delay = 1000000 / refresh;

	wlr_output_update_custom_mode(&output->wlr_output, width, height, refresh);
	return true;
}

static bool output_test(struct wlr_output *wlr_output,
		const struct wlr_output_state *state) {
	uint32_t unsupported = state->committed & ~SUPPORTED_OUTPUT_STATE;
	if (unsupported != 0) {
		wlr_log(WLR_DEBUG, "Unsupported output state fields: 0x%"PRIx32,
			unsupported);
		return false;
	}

	if (state->committed & WLR_OUTPUT_STATE_MODE) {
		assert(state->mode_type == WLR_OUTPUT_STATE_MODE_CUSTOM);
	}

	return true;
}

static bool output_commit(struct wlr_output *wlr_output,
		const struct wlr_output_state *state) {
    void *data = NULL;
    uint32_t drm_format;
    size_t stride;
	struct wlr_fbdev_output *output =
		fbdev_output_from_output(wlr_output);

	if (!output_test(wlr_output, state)) {
		return false;
	}

	if (state->committed & WLR_OUTPUT_STATE_MODE) {
		if (!output_set_custom_mode(output,
				state->custom_mode.width,
				state->custom_mode.height,
				state->custom_mode.refresh)) {
			return false;
		}
	}

	if (state->committed & WLR_OUTPUT_STATE_BUFFER) {
		struct wlr_output_event_present present_event = {
			.commit_seq = wlr_output->commit_seq + 1,
			.presented = true,
		};

        // display buffer,just memcpy to framebuffer
        if (!wlr_buffer_begin_data_ptr_access(state->buffer, WLR_BUFFER_DATA_PTR_ACCESS_READ,
                &data, &drm_format, &stride)) {
            return false;
        }

#if 1
		pixman_region32_t *damage = NULL;
		if (state->committed & WLR_OUTPUT_STATE_DAMAGE) {
		    damage = (pixman_region32_t *) &state->damage;
		    int rects_len;
            pixman_box32_t *rects = pixman_region32_rectangles(damage, &rects_len);

            // update the dirty regions
            for (int i = 0; i < rects_len; i++) {
                pixman_box32_t *box = &rects[i];
                int rect_stride = (box->x2 - box->x1 ) * (output->bpp / 8);
                int rect_y = box->y2 - box->y1;
                void *rect_addr = data + (stride * box->y1) + (box->x1 * output->bpp / 8);
                void *fb_addr = output->fb_addr + (stride * box->y1) + (box->x1 * output->bpp / 8);

                // display new data
                for (int j = 0; j < rect_y; j++) {
                    memcpy(fb_addr, rect_addr, rect_stride);
                    rect_addr += stride;
                    fb_addr += stride;
                }
            }
        }
#else
        memcpy(output->fb_addr, data, output->width * output->height * output->bpp / 8);
#endif

        wlr_buffer_end_data_ptr_access(state->buffer);

		wlr_output_send_present(wlr_output, &present_event);
	}

	wl_event_source_timer_update(output->frame_timer, output->frame_delay);

	return true;
}

static void output_destroy(struct wlr_output *wlr_output) {
	struct wlr_fbdev_output *output =
		fbdev_output_from_output(wlr_output);
	wl_list_remove(&output->link);
	wl_event_source_remove(output->frame_timer);
	free(output);
}

static const struct wlr_drm_format_set *output_get_primary_formats(
        struct wlr_output *output, uint32_t buffer_caps) {
    wlr_drm_format_set_add(&output_fmt_set, DRM_FORMAT_RGB565, DRM_FORMAT_MOD_INVALID);
    wlr_drm_format_set_add(&output_fmt_set, DRM_FORMAT_XRGB8888, DRM_FORMAT_MOD_INVALID);
    return &output_fmt_set;
}

#if 0
static const struct wlr_drm_format_set *output_get_formats(
        struct wlr_output *wlr_output, uint32_t buffer_caps) {
    printf("!!! %s %d\n", __func__, __LINE__);
    return NULL;
}

static bool output_set_cursor(struct wlr_output *wlr_output,
        struct wlr_buffer *wlr_buffer, int hotspot_x, int hotspot_y) {
    printf("!!! %s %d\n", __func__, __LINE__);
    return true;
}

static bool output_move_cursor(struct wlr_output *_output, int x, int y) {
    printf("!!! %s %d\n", __func__, __LINE__);
    return true;
}
#endif

static const struct wlr_output_impl output_impl = {
	.destroy = output_destroy,
	.commit = output_commit,
#if 0
    .set_cursor = output_set_cursor,
    .move_cursor = output_move_cursor,
	.get_cursor_formats = output_get_formats,
#endif
    .get_primary_formats = output_get_primary_formats,
};

bool wlr_output_is_fbdev(struct wlr_output *wlr_output) {
	return wlr_output->impl == &output_impl;
}

static int signal_frame(void *data) {
	struct wlr_fbdev_output *output = data;
	wlr_output_send_frame(&output->wlr_output);
	return 0;
}

struct wlr_output *wlr_fbdev_add_output(struct wlr_backend *wlr_backend,
		char *dev_name) {
    unsigned int width, height;
    LW_GM_VARINFO var;
	struct wlr_fbdev_backend *backend =
		fbdev_backend_from_backend(wlr_backend);

	struct wlr_fbdev_output *output =
		calloc(1, sizeof(struct wlr_fbdev_output));
	if (output == NULL) {
		wlr_log(WLR_ERROR, "Failed to allocate wlr_fbdev_output");
		return NULL;
	}

	// open fbdev
	output->fd = open(dev_name, O_RDWR, 0777);
	if (output->fd < 0) {
        wlr_log(WLR_ERROR, "Failed to open fbdev %s", dev_name);
        free(output);
        return NULL;
	}

	// get framebuffer format
	if(ioctl(output->fd, LW_GM_GET_VARINFO, &var)) {
        wlr_log(WLR_ERROR, "LW_GM_GET_VARINFO ioctl fail");
        close(output->fd);
        free(output);
        return NULL;
	}

    // init output size
    width  = var.GMVI_ulXRes;
    height = var.GMVI_ulYRes;

    output->width   = width;
    output->height  = height;
    output->bpp     = var.GMVI_ulBitsPerPixel;
	output->fb_addr = mmap(0,
	                       width * height * var.GMVI_ulBytesPerPixel,
                           PROT_WRITE | PROT_READ,
                           MAP_SHARED, output->fd, 0);
	if (output->fb_addr == MAP_FAILED) {
        wlr_log(WLR_ERROR, "Failed to mmap fbdev");
        close(output->fd);
        free(output);
        return NULL;
	}

	output->backend = backend;
	wlr_output_init(&output->wlr_output, &backend->backend, &output_impl,
		backend->display);
	struct wlr_output *wlr_output = &output->wlr_output;

	// init output pixel fmt
    if (var.GMVI_ulBitsPerPixel == 16) {
        wlr_output->render_format = DRM_FORMAT_RGB565;
    } else {
        wlr_output->render_format = DRM_FORMAT_XRGB8888;
    }

	output_set_custom_mode(output, width, height, 0);

	char name[64];
	snprintf(name, sizeof(name), "FBDEV-%zu", ++backend->last_output_num);
	wlr_output_set_name(wlr_output, name);

	char description[128];
	snprintf(description, sizeof(description),
		"SylixOS fbdev output %zu", backend->last_output_num);
	wlr_output_set_description(wlr_output, description);

	struct wl_event_loop *ev = wl_display_get_event_loop(backend->display);
	output->frame_timer = wl_event_loop_add_timer(ev, signal_frame, output);

	wl_list_insert(&backend->outputs, &output->link);

	if (backend->started) {
		wl_event_source_timer_update(output->frame_timer, output->frame_delay);
		wlr_output_update_enabled(wlr_output, true);
		wlr_signal_emit_safe(&backend->backend.events.new_output, wlr_output);
	}

	return wlr_output;
}
